1. Field of the Invention
The present disclosure is related to a keyboard and a key module thereof, and more particularly to a key module having a movable switch mechanism which not only can be used to guide a keycap to move upwards or downwards, but also brings a circuit into conduction to induce a signal when the key module is depressed.
2. Description of Related Art
A general keyboard used for computers usually uses a plastic dome disposed between a keycap and a circuit membrane. The plastic dome is used to return the keycap to its original position with an upward restoring force and cause the bottom of the keycap to touch the circuit membrane to induce a conductive signal. This kind of keyboard provides a better typing tactility with a longer stroke or travel distance, but has a higher total height.
Further, compact keyboards, such as those used for mobile phones or portable electronic devices, usually include a metal dome disposed between the keycap and the circuit membrane. When the keycap is pressed, a rod on the bottom surface of the keycap abuts against the metal dome and presses the metal dome downwards to contact the circuit membrane to produce a conductive signal. This kind of keyboard provides a rough and poor typing tactility with a shorter travel distance. Moreover, if the metal dome is excessively squeezed or repeatedly withstands compressive loads, it may easily experience fatigue of material and have a shortened service life.